The growing concern of society with sustainability has intensified the control of products that are harmful to the environment. Therefore, products containing ethoxylated alkylphenols, widely used in cleaning agents and household detergents, have been subject to severe restrictions and prohibitions in many parts of the world over the years.
Problems related to the preservation of the environment, biodegradability and harmful effects on human health have been reported, motivating the substitution of ethoxylated alkylphenols by less harmful and aggressive compounds.
Biodegradable products are those that tend to degrade naturally, that is, they have natural conditions allowing them to incorporate again to the soil.
In this regard, ethoxylated Guerbet alcohol-based surfactants are indicated as substitutes for ethoxylated alkylphenols. These surfactants have excellent wetting power, emulsifying action, low odor and excellent solubilization of oils and fats.
Ethoxylation is an industrial process in which ethylene oxide is added to fatty alcohols to obtain detergent properties. In an industrial ethoxylation, an alcohol is treated with ethylene oxide and potassium hydroxide (KOH), which acts as a catalyst. The reactor is pressurized with nitrogen and heated at approximately 150° C.:ROH+nC2H4O→R(OC2H4)nOH
A product distribution is obtained. These products are important non-ionic surfactants, since they have both lipophilic “tails” (R in the equation) and a relatively polar group in the “head” ((OC2H4)nOH in the example above). The amount of ethylene oxide and the reaction time determine the degree of ethoxylation, which in turn determines the properties of the ethoxylated surfactant. Traditionally, alcohols are obtained by hydrogenation of fatty acids, and also by “oxo alcohols” obtained via hydroformylation.
Guerbet Alcohol
Guerbet alcohols have been known since 1890 when Marcel Guerbet first synthesized such compounds. The reaction that bears its name occurs at high temperatures in the presence of alkaline catalysts. The global reaction can be renresented by the following equation:
  2  ⁢            R      ⁢      CH        2    ⁢      CH    2    ⁢  OH  ⁢          ⁢      Δ    catalisador    ⁢      R    2    ⁢      CHCH    2    ⁢  OH
The product is an alcohol with essentially twice the molecular weight. The reaction proceeds by a number of sequential steps that are: (1) oxidation of the alcohol to aldehyde; (2) aldehyde aldol condensation; (3) dehydration of the aldol product; and (4) hydrogenation of the allelic aldehyde.
Since they are branched and of high molecular weight, Guerbet alcohols have the following characteristics:
have low irritation potential;
are liquid at extremely low temperatures;
have low volatility;
are reactive and can be used to make many derivatives;
are good lubricants.
The prior art provides some options for using Guerbet alcohols and Guerbet alcohols mixtures with other alcohols for cleaning formulations. Among them, it is possible to highlight the three documents mentioned below.
Document No. EP 2 264 138 A1 discloses a dishwashing detergent composition comprising a chelator and a surfactant system. The surfactant system is contained in an amount ranging from 18% to 80% by weight of the total composition and comprises nonionic surfactants such as C8-C22 aliphatic alcohols and branched alcohols such as, for instance, Guerbet alcohols.
Document No. WO 96/18711 A1 describes a cleaning composition for hard surfaces comprising surfactants derived from highly ethoxylated Guerbet alcohols with from 7 to 30 moles of ethylene oxide per mole of alcohol. It is further described that nonionic and non-Guerbet surfactants are contained in an amount ranging from 0.5% to 10% of the cleaning composition.
Document No. WO 2014/085271 A1 relates to a laundry detergent using an APE (alkylhenol ethoxylate)-free surfactant comprising from 40% to 95% by weight of a mixture of nonionic surfactants, wherein the mixture comprises an ethoxylated linear fatty alcohol, an ethoxylated branched fatty alcohol and an ethylene oxide-propylene oxide copolymer.
Currently, the most commonly used nonionic surfactants in surface cleaning formulations are ethoxylated linear alcohols of C9-C11 chain size of strictly petrochemical origin, produced from olefins derived from ethene.
Thus, we find that the technique still requires a nonionic surfactant composition to be used in environmentally friendly surface cleaning formulations using natural alcohols.